This invention relates generally to entryway systems for homes and commercial buildings and more specifically to continuous threshold assemblies of entryway systems.
Entryway systems used in building construction generally include a pair of vertically extending door jambs and a head jamb that frame the entryway and receive a hinged door. An elongated threshold assembly is attached at its ends to the bottoms of the door jambs and spans the bottom of the entryway. Many modern threshold assemblies include an extruded aluminum frame having an upwardly open channel from which a sill slopes outwardly and downwardly. A wood or composite foundation or, in some cases, just support blocks are attached at spaced intervals to the underneath side of the frame to provide support and rigidity to the assembly. A threshold cap, which may be made of plastic or wood, is disposed in the upwardly open channel and underlies a closed door mounted in the entryway. The threshold cap usually is vertically adjustable to engage and form a seal with a flexible sweep attached to the bottom of the door.
Traditionally, the bottoms of door jambs, which usually are made of wood, have been attached to the ends of the threshold assembly by milling a specially shaped haunch in the jamb bottom ends to accommodate the profile of the threshold assembly and fitting and stapling the milled bottoms of the jambs to the threshold assembly. A portion of the haunch overlaps and sits atop the sloped sill deck of the threshold assembly. Problems with this traditional technique are many. For instance, since virtually every brand and style of threshold assembly has a different shape with a sill deck that extends at a different angle, the jamb haunches in each case must be precisely and specially milled to fit the particular threshold assembly to which they are to be attached. This means that pre-hangers must own and operate expensive and accurate milling machinery and must maintain a number of different shaped milling cutters to accommodate the various configurations of threshold assemblies.
Recently, a need has been recognized for an entryway system designed to eliminate the requirement that jamb bottoms be accurately milled to mate with the ends of a threshold assembly. Related needs include the standardization of jamb length for a wide variety of threshold designs such that pre-hangers do not have to stock different length jambs, and the need to inhibit rotting and deterioration due to water collection at the junction of the jambs and the threshold assembly. In response to these and other needs, we have previously proposed a plastic jamb boot that attaches to each end of the extruded aluminum threshold frame. Our proposed jamb boot is described in detail in our pending U.S. patent application Ser. No. 09/902,042 entitled Threshold Assembly with Pre-fitted Draining Jamb Boots and Pre-fitted Mull Boots, the disclosure of which is hereby incorporated by reference (hereinafter the xe2x80x9cincorporated referencexe2x80x9d).
Essentially, the jamb boot disclosed in the incorporated reference is an injection molded plastic attachment that is preformed with the appropriately configured haunch for mating with the end of a jamb. The jamb boot has a flat upper surface to which a square cut bottom end of a wooden jamb is attached. The jamb boot, which also may incorporate draining features, prevents moisture contact with the bottoms of the wooden jambs, allows wooden jambs to have simple square cut rather than accurately milled bottom ends, and provides for the standardization of jamb length for a wide variety of threshold assembly designs.
While our plastic jamb boot addresses many of the problems discussed above, other problems still persist. For example, the manufacturing steps required to attach a wood substrate or to attach wooden or composite support blocks to the underneath side of an extruded aluminum threshold are labor intensive. Further, since these components rest directly on a subfloor when the threshold is installed, they can soak up moisture and rot or deteriorate over time. When this happens, the substrate or support blocks can swell, which causes the aluminum threshold to deform or rack in place. Other problems exist such as, for example, the labor intensive process of installing screw bosses or T-nuts in the region of a wood substrate that forms the floor of the threshold cap channel for receiving the adjusting screws of the threshold cap.
A need persists, therefore, for a threshold assembly that may incorporate all the aforementioned advantages of plastic jamb boots attached to traditional threshold assemblies, and also that incorporates efficient draining features, eliminates the need and manufacturing steps involved in attaching support blocks and wooden substrates to the underside of aluminum frames, that eliminates swelling and deterioration of a substrate in the presence of moisture, and generally that simplifies the fabrication process and results in a threshold assembly of superior durability and quality. It is to the provision of such a threshold assembly and to an entryway system that incorporates such an assembly that the present invention is primarily directed.
Briefly described, the present invention, in a preferred embodiment thereof, comprises a unique threshold assembly for installation in an entryway spanning the bottom ends of the vertical jambs of the entryway. The threshold assembly includes an elongated preferably compression molded unitary plastic body that is formed to define an upwardly open channel along its inside edge portion for receiving a threshold cap. The body further forms a support substrate that extends forwardly from the channel to an outside edge. An interior trim or nosing is integrally formed along the interior edge of the plastic body and defines the inside wall of the upwardly open channel. In one embodiment, a jamb boot is integrally molded at either end of the plastic body. Each jamb boot is profiled to match the profile of a wood jamb and has a level flat top surface for attaching the jamb boot to a square-cut bottom end of a wooden jamb with screws. An extruded aluminum sill plate is snapped into place on the plastic body covering and supported by at least a portion of the support substrate. When so attached, the sill plate projects outwardly and slopes downwardly from the upwardly open channel in the traditional way to provide a safe and durable tread surface.
In one embodiment, a sill plate attachment slot is formed along the junction between the upwardly open channel and the support substrate and the aluminum sill plate is formed with a barbed tab or flange that is received and secured within the attachment slot. The attachment slot communicates with transverse drain channels formed at the ends of the support substrate and these drain channels extend to the outside edge of the assembly. The drain channels collect rainwater and direct it away from the threshold assembly to prevent rot and deterioration of the sub-floor beneath the threshold assembly. In another embodiment, the sill plate is formed with a vertical wall along its inside edge that forms the outside wall of the upwardly open channel when the sill plate is installed. The slot is formed along the bottom outside corner of the channel by an array of inwardly projecting tabs and the wall of the sill plate has a downwardly extending portion that covers the tabs and snaps into the slot. In this embodiment, an upwardly extending portion of the wall forms a dam and the outside wall of the upwardly open channel.
The molded plastic body may be configured in a variety of ways. For example, the support substrate may be formed with a block or open rib structure or with a full or closed rib structure, or it may be solid. The support substrate may be formed with substantially solid end portions sized to accommodate cutting, honing, and notching. Mull post support regions may be formed in the support substrate for underlying and supporting and for providing an attachment location for mull posts or mull boots in sidelight entryways. In any event, the body preferably is formed by a compression molding process from slightly blown or cellular plastic, which may include a filler such as wood flour, rice hulls, or equivalents thereto. A traditional threshold cap is disposed in the upwardly open channel and a plastic nosing cover may be snapped in place over the inside nosing to provide a pleasing interior appearance. When assembled, the threshold assembly of the invention resembles a traditional continuous threshold assembly, but is far simpler to assemble, is resistant to rot, swelling, and warpage, and has a longer expected life than prior art threshold assemblies.